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gi-hepatology

Crohn's Disease Activity Index (CDAI)

Measures Crohn's disease activity over one week. The standard index for clinical trials. Remission: <150. Moderate-severe disease: 220–450. Severe: >450.

Used in: Inflammatory Bowel Disease

Total count of liquid or very soft stools over the past 7 days

0=none, 1=mild, 2=moderate, 3=severe — daily score × 7 days, max 21

0=generally well, 1=slightly below par, 2=poor, 3=very poor, 4=terrible — daily × 7 days, max 28

Count each present: arthritis/arthralgia, iritis/uveitis, erythema nodosum/pyoderma/aphthous stomatitis, anal fissure/fistula/abscess, other fistula, fever >37.8°C, use of anti-diarrhoeal drugs, palpable abdominal mass

Normal is ~47% for men and ~42% for women

Positive if below ideal weight. E.g., if 10% below ideal weight, enter 10. If above ideal, enter 0.

Score interpretation

Remission 0–149

CDAI <150 — clinical remission

→ Maintain current therapy; routine monitoring

Mild Disease 150–219

CDAI 150–219 — mild active disease

→ Optimise current therapy; consider step-up; monitor closely

Moderate-Severe Disease 220–450

CDAI 220–450 — moderate to severe disease

→ Intensify therapy (biologics, steroids); gastroenterology review; consider hospital admission

Severe Disease ≥ 451

CDAI >450 — severe disease

→ Urgent hospitalisation; IV steroids or biologic induction; surgical consultation

Interpretation bands for the CDAI. Apply clinical judgement and local guidance.

References

Related

Curated clinical cross-links plus same-class fallbacks.

Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.